Russia is using civilian-plated trucks to transport "mercenaries" from North Korea to frontline areas, Ukraine's military intelligence service reported, amid concerns that North Korean troops might join combat in Russia's war on Ukraine.

On Sunday, Russian police reportedly stopped a truck with civilian license plates carrying North Korean military personnel on the Kursk-Voronezh highway, noting that the driver lacked a combat order, according to Ukraine's Defense Intelligence.

This development follows reports of North Korean troops gathering in Russia's Kursk region, where a significant Ukrainian incursion occurred in August.

Last week, South Korea's intelligence agency disclosed that 3,000 North Koreans have been sent to Russia, with a total of around 10,000 expected by December. The United States also confirmed the deployment of at least 3,000 North Koreans to eastern Russia this month.

In response to the growing military cooperation between North Korea and Russia, South Korea has pledged to take "phased measures." President Yoon Suk Yeol suggested that Seoul could consider supplying arms to Kyiv, potentially marking a shift from its current policy of providing only humanitarian aid. (Yonhap)